Bulk Ring-Opening Copolymerization of L-Lactide and Glycolide Catalyzed by Bismuth/Tin
To investigate the effects of metal catalysts Sn(Oct)2 and bismuth salicylate(BiSS)on the reaction process and product properties of bulk ring opening polymerization(ROP)of L-lactide(L-LA)and glycolide(GA),a series of polylactide glycolide copolymers(PLGA)were synthesized using different amounts of Sn(Oct)2 or BiSS.The microstructure,polymerization kinetics and molecular weight of the polymer were characterized by NMR,FT-IR and gel permeation chromatography.The thermal stability of the polymer was analyzed by thermogravimetry and differential scanning calorimetry.The results show that BiSS is a very attractive catalyst,and its catalytic performance similar results are comparable to that of Sn(Oct)2 in the preparation of PLGA.The thermal stability of PLGA prepared with BiSS catalysis is significantly improved.For example,the T5%and T90%of PLGA73 prepared with 1000×10-6 Bi catalysis in nitrogen atmosphere are 269.6℃ and 379.2℃,respectively,which are increased by 36℃ and 82.7℃ compared to those of Sn(Oct)2,respectively.The PLGA segments prepared with BiSS catalysis exhibit higher randomness and shorter L-LA sequence length.BiSS can replace commercially used Sn(Oct)2 for the production of low toxicity PLGAs for biomedical applications.
NETL
NSTL
万方数据
